1. Field of the Invention
The present invention relates to a revised structure for a compound protective helmet, and more particularly, to one allows the restriction device to secure firmly to the chin protector without loosening up or falling off, and better hooking and restricting effects of the restriction device than before
2. Description of the Prior Art
Whereas, in the prior art of the compound protective helmet, the inadequate structural design leads to poor restriction effects and inconsistent operation. The present inventor thus improves the prior art by tackling the defectives, and publishes the .left brkt-top.Compound Protective Helmet.right brkt-bot., which has been filed for an utility patent, allotted Ser. No. 09/425,137, to the US Patent Office. Said application has been examined with positive outcomes of better and more stable restriction effects than the prior art, and has been awarded a patent. The prevent inventor feels no complacent about the achievement and continues to investigate possible improvement of said case restlessly. Consequently, some of the structural designs that can be further improved have been discovered.
Referring to the original descriptions and drawings of the patent, the original compound protective helmet is essentially comprised of a bubble 1, a visor 2, which can allow two-stage lift, and a chin protector 3 are pivoted to the bubble 1; within, a restriction device 4 is fixed at the inner edge of the chin protector 3 to become a full mask protective helmet. Though the prior art gives consistent visor lift operation and firm restriction of the visor when closed, the following defectives in terms of its structural design and practical use are found:
1. The whole set of restriction device 4 can only be restricted by two limit pieces 461 on the left and right, and the limit pieces also make a restriction lever 44 insert into a guide rail 412 and fix at the inner edge of the chin protector 3. The whole design is not solid enough to ensure a firm connection. PA1 2. The end of the restriction lever 44 is a shape of simple strip; at the state of full mask protective mask, the restriction lever 44 is inserted into the restriction trough 141 at both sides of the bubble 1, without having real restricting and positioning effects. If the chin protector 3 is under externally applied force, the restriction lever 44 retreating from the restriction trough 141 can easily occur. PA1 3. Two slope positioning arcs 45 are protruding inside the chin protector 3; the configuration increases not only the difficulty in making die for the chin protector 3, but also the possibility of striking or breaking of the slope positioning arcs 45.
According to the foregoing, the present inventor tries to improve the chin protector 3 and the restriction device 44. Consequently, numerous trials and modifications lead to the publication of the present invention.